RT Journal Article ID 55bd3d44237d1b54 A1 Sunu, Putu Wijaya A1 Wardana , I. N. G. A1 Sonief, A. A. A1 Hamidi, Nurkholis T1 The Effect of Wall Groove Numbers on Pressure Drop in Pipe Flows JF International Journal of Fluid Mechanics Research JO FMR YR 2015 FD 2015-04-10 VO 42 IS 2 SP 119 OP 130 AB Flow behavior in pipe with rectangular grooves on internal wall surface has been investigated experimentally. The number of grooves was varied to clarify its influence on pressure drop. In this experimental design, dyes were injected from pipe walls and plastic threads attached to internal pipe walls to enable observation of their movements in flowing water. Results show that pipe wall grooves, described as 2n and 2n + 2m did induce pressure drops. When n is the odd positive integer the groove produces weak vortices of low momentum viscous fluid on the wall which diameter is larger than the groove spacing. Therefore, it is swept by large-scale motion from the center of the pipe then pressure drop decreased. However, when n equals to the even positive integer the groove produces energetic small vortices of high viscous fluids that rotates around the pipe wall and induces high momentum fluid from the center of the pipe. As a result, the radial velocity increased as did the pressure drop. m represented the motion that interrupting flow behavior caused by n. When n is the odd positive integer, the vortex behavior represented with m tended to increase the pressure drop produced by n. On the other hand, when n is the even positive integer, m tended to decrease pressure drop produced by n. PB Begell House LK https://www.dl.begellhouse.com/journals/71cb29ca5b40f8f8,304222ec597a09e9,55bd3d44237d1b54.html